[Haskell-beginners] Couldn't match expected type ‘IO ()’ with actual type [Integer]

[Nadir Sampaoli]

"Roelof Wobben":
>
> I have this :
>
> -- | Main entry point to the application.
> module Main where
>
>
> -- | convert a number to a array in pieces where a negative number will
be a empty array.
> toDigits :: Integer -> [Integer]
> toDigits n
>   | n < 0 = []
>   | otherwise = n/10 : []
>
> -- | The main entry point.
> main :: IO ()
> main = do
>     toDigits 123

First of all, what do you expect from your program?

The problem with your code is that `main` declares type `IO ()` in its
signatures but its body has another type, [Integer].

What do you think is wrong with the compiler's output?

--
Nadir
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